Radiation resistant compounds


Tests conducted on various seal materials for nuclear service, indicate that no elastomer can be expected to give lengthy service after a total dosage of 10^7 R of gamma radiation due to severe degradation to physical properties and compression set. However, some elastomeric materials such as ethylene propylene give an indication of useful service life after an exposure to a total dosage of10^7 Rof gamma radiation. (Gamma radiation has the worst affect on elastomeric materials.)

Since many applications requiring exposure to radiation also require exposure to fluids such as water and silicone fluids, special ethylene propylene compounds are widely used for seals in nuclear service. Other materials such as fluorocarbon and some special nitrile compounds have found limited service for applications requiring resistance to other media.

Many of the fission fragments produced when atoms are split (fissioned) are unstable and release radiation to achieve stability. Once an atom reaches stability, it is no longer radioactive. More specifically, there are three major forms of radiation:
alpha particles
beta particles and
gamma rays.

Alpha radiation
Alpha radiation consists of particles with a positive electric charge. They readily collide with and are stopped by the atoms and molecules in the matter they encounter. These alpha particles can be stopped by the first layer of skin, a few inches of air or a sheet of paper.

Beta radiation
Beta radiation consists of particles with a negative electric charge. Because they are slightly faster and smaller, beta particles can travel a little farther than alpha particles. However, wood or a thin sheet of metal can block these particles.

Gamma radiation

Gamma radiation is an electromagnetic ray similar to, but stronger than, X-rays. Gamma radiation can easily pass through the human body, but can be stopped by lead several inches thick or concrete several feet thick.

Ionization

From the standpoint of health and safety, concern about radiation stems from its ability to ionize other elements. Ionization involves the change of the electron structure of an atom. Radiation can knock electrons from their orbit, altering atoms and molecules (groups of atoms). Depending on type and quantity, uncontrolled radiation can damage the human body or environment.

Made-to-order special parts. Custom tooling fee and lead time apply.